This study explores the application of a blockch-ain-based digital forensics architecture using the DIKW (Data, Information, Knowledge, Wisdom) graph in police investigations. Current digital intelligence systems usually plan a route from Data Governance to Wisdom Governance, but ignore or lack I nformation Governance. From a conceptual semantic perspectiv -e [1], the concepts underlying these domains include Data, Information, Knowledge, Wisdom(DIKW) [2]. With the development of blockchain technology and the Internet of Things, digital forensics plays a crucial role in criminal investigations. Existing methods face challenges in terms of flexibility in storing evidence on the blockchain and efficient handling of large-scale and multimodal forensic demands. To address these issues, the DIKW (Data, Information, Knowledge, Wisdom) graph model is introduced. The DIKW graph is a multi-layered hierarchical structure for processing typed resources, consisting of data graph, information graph, knowledge graph, and wisdom graph [3]. It can be used to optimize the efficiency of storage, trans mission, and computation integration [4], as well as for privacy data protection [5]. The methods include the integration of the Internet of Thi -ngs (IoT) and blockchain, as well as the design of a blockcha -in-based digital forensics architecture using the DIKW (Data, Information, Knowledge, Wisdom) graph. The data layer is responsible for collecting and storing data generated b y IoT devices. The results show that this architecture im proves the efficiency and accuracy of digital forensics an d provides strong decision support for law enforcement.